England skipper Alastair Cook is under a great deal of pressure going into the India series, having been heavily criticised recently both for his captaincy and his poor batting form.

His skills as a captain have been consistently questioned, and the criticism has ramped up since the thrashing by Australia and further after the series loss to Sri Lanka, with spin-bowling legend Shane Warne's appraisal particularly damning, per the Telegraph:

However, more worrying for Cook and England has been the Essex man's form with the bat of late, which has sparked calls from some corners for him to be dropped from the side.

At just 29 years old, Cook is already England's fifth-highest Test runs scorer of all time with 8,125 in his career thus far, per ESPNcricinfo, and he should move up at least two places by the end of the series, per Opta:

Thus, there is no doubt that he is a great batsman. However, the last year has seen him hit some terrible form, per OptaPro:

"When he edged Shaminda Eranga behind in the second innings of the opening Test of the summer at Lord’s, his average over a 12-month period stood at 25.8, 20.4 runs below his career average of 46.2."

Failure to perform against India could see him genuinely considered as a candidate for the drop, and thus a process would have to begin of finding a new captain for England and further disrupt the side after a torrid winter.

Conversely, however, a return to form for Cook could both seal his place in the side and as captain, as it could be the key to an England series victory.

Cook's recent failures have gone hand in hand with England's demise, and his revival could be the boost they need to get back to winning form in Test matches.

In the 2010-11 Ashes series, he scored 766 runs in just seven innings at an average of 127.66, per Opta via The Guardian, and England trounced Australia 3-1—all of their victories coming by an innings and runs.

Equally, when England took their first series victory in India since 1985—a 2-1 win in 2013—Cook was the top run-scorer in the series.

When Cook performs at the top of the order, England score big, and when England score big, they win.

A series victory over India would assure Cook's place as captain, and a return to form for him could be the key factor.

A big score in the first Test at Trent Bridge could set him—and his team—up for a fine summer. Another failure, and the pressure will mount even more.